Astrophotography Editing in 10 Minutes | Photoshop Tutorial

Summary

Nick demonstrates a fast, beginner-friendly Photoshop workflow for bringing out detail in a stacked astrophotography image. The example is a five-hour image of the North American Nebula, stacked in DeepSkyStacker and captured with a modified Canon 650D.

He emphasizes that this is a quick “good enough” edit, not his complete processing method. The tutorial moves quickly, so viewers may want to pause as needed. He also notes that astrophotography processing is subjective and that the image could be refined further with more time.

Editing workflow

1. Convert the image

   • Change the image from 32-bit to 16-bit.
   • Choose Exposure and Gamma as the conversion method and leave the settings at their defaults.
   • Keep an eye on the histogram during editing.

2. Adjust Levels and Curves

   • Use a Levels adjustment, working on each color channel individually.
   • Move the black-point sliders inward only partway. Avoid pushing the data all the way to the left, so there is room for later adjustments.
   • Add a Curves adjustment to stretch the image and reveal faint nebula detail.
   • After each Curves adjustment, revisit Levels and refine the individual channels.
   • Repeat this process gradually rather than making one extreme adjustment.

3. Reduce star size

   • Select Select → Color Range → Highlights.
   • Keep fuzziness at about 20 and adjust the selection to capture many stars without selecting much of the nebula.
   • Apply Filter → Other → Minimum, using a small radius of roughly 2 pixels and preserving roundness.
   • Reduce the effect’s opacity if the stars shrink too much.

4. Sharpen the stars

   • Apply Filter → Sharpen → Smart Sharpen.
   • Nick’s usual settings are Amount 200%, Radius 1, and Reduce Noise 0.

5. Enhance the nebula with actions (optional)

   • Nick uses two actions from the Astronomy Tools action set. The set is paid, but the workflow can still be followed without it.
   • Run Lighten Only DSO and Dimmer Stars, then lower the effect’s opacity substantially—around 40% in this example.
   • Recheck Levels on the individual channels.
   • Run Enhance DSO and Reduce Stars. Nick uses the default settings, then reduces the action’s opacity to around 30% to avoid an overprocessed look.
   • Check Levels again afterward, since these actions can brighten the background.

6. Finish the color and contrast

   • Increase saturation slightly—about 10 in this example—to deepen the nebula’s red.
   • Make a final Curves adjustment to tone down an overly bright background while retaining the nebula’s brightness.
   • Save the finished image as a PNG.

Main takeaways

• Gentle, repeated Levels and Curves adjustments can reveal substantial detail from a stacked image.
• Lowering a layer’s opacity is a useful way to moderate strong processing effects.
• The histogram and individual color channels help guide adjustments throughout the workflow.
• A quick edit can produce a reasonable result, but it may leave artifacts or uneven areas that would benefit from more careful refinement.
• The final appearance is a matter of taste. This ten-minute process is a practical starting point, not a definitive or complete method.

Speakers and sources featured

• Nick — presenter and narrator from AstroExploring.
• Software and tools: Adobe Photoshop 2021, DeepSkyStacker, and the Astronomy Tools action set.